Golden shade from polyesters process for the manufacture of filaments and fibers having a metallic

ABSTRACT

FILAMENTS AND FIBERS MADE FROM HIGH MOLECULAR WEIGHT SYNTHETIC LINEAR POLYESTERS HAVE A METALLIC GOLDEN ASPECT WHEN THESE CONTAIN FROM 0.001 TO 0.01% BY WEIGHT OF NIOBIUM BASED ON INCORPORATED NIOBIUM PENTOXIDE. SUCH FILAMENTS AND FIBERS ARE PREFERABLY OBTAINED BY ADDING NIOBIUM PENTOXIDE HYDRATE HAVING A DETERMINED WATER CONTENT DURING THE NORMAL POLYESTER PREPARATION PROCESS IN AN AMOUNT WHICH YIELDS A NIOBIUM CONTENT OF FROM 0.001 TO 0.01% BY WEIGHT IN THE POLYESTER END PRODUCT, AND BY SUBSEQNENTLY PROCESSING THE POLYESTER SO OBTAINED BY MELT SPINNING. ESPECIALLY MONOFILAMENTS HAVING A GOLDEN SHADE ARE USED AS FASTENING LINKS OF ZIPPERS.

'U.S. Cl. 260-40 P United States P t Ofice 3,758,438 Patented Sept. 11, 1973 3,758,438 PROCESS FOR THE MANUFACTURE OF FILA- MENTS AND FIBERS HAVING A METALLIC GOLDEN SHADE FROM POLYESTERS Gerhard Freitag, Niederhofheim, Taunus, Germany, as-

siguor to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Bruning, Frankfurt am Main, Germany No Drawing. Filed Dec. 10, 1971, Ser. No. 206,940 Claims priority, application Germany, Dec. 12, 1970, P 20 61 354.1 Int. Cl. C08g 51/04 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a process for the manufacture of filaments and fibers having a metallic golden shade from polyesters.

Filaments and fibers having metallic color shades are known in many variations; however, difficulties often arise during their manufacture, and the color shades often do not meet the requirements.

In dyeing baths, especially coarse-titer filaments are dyed only superficially. The color film formed often shows differences in its intensity, which difiences, upon friction, increase, so that finally the dyed surface layer is destroyed.

It is also possible to apply metals to filaments by means of steam (cf. W. Goldie, Plaste und Kauschuk 15, 1958, No. 10, pp. 738-740). However, the metallized surfaces hardly resist abrasion. Moreover, the metallic character of the colors often is lost during the steam treatment: the results are brown shades instead of golden ones, or grey shades instead of silver ones.

A similar behaviour can be observed when metal powder is pulverized on chips made from synthetic linear polymers and when these chips are spun-hereinafter called spinning-in to put it briefiy, or when metal powder is added during the preparation of the polymers and when the polymers so dyed are spunhereinafter called condensing-in to put it briefly. Gold and silver bronzes used in these techniques generally also yield brown and grey shades, respectively. Moreover, the filaments, in the drawing operation, often are cut in the direction of feed by the sharp-edged metal particles, which deteriorates their performance characteristics and especially enhances the tendency to splicing.

By spinning-in or condensing-in of pigments or pigment blends, abrasion-proof gold shade dyeings of polymers in the mass can be obtained. The main drawback of this process resides in the fact that just the pigments of interest for the dyeing of gold shades, for example PV Fast Orange GRL: Colour Index 71105; Group Vat Orange 7 are of a limited temperature resistance and partially de compose in the polymer preparation process which generally is carried out at elevated temperatures, and especially in the melt spinning process. The results are alterations of the shade on the one hand, and on the other great differences of the specific viscosities of the polymer caused by the catalytic influence of the decomposition products. The reproducibility of specific viscosity and shade of the chips and filaments therefore is very poor.

Hence, it is the object of the present invention to provide filaments and fibers having a metallic golden shade which do not have the aforementioned drawbacks.

This object of the invention is attained by means of filaments and fibers made from high molecular weight synthetic linear polyesters containing of from 0.001 to 0.01% by weight of niobium.

Furthermore, it has been found that such filaments and fibers made from high molecular weight synthetic linear polyesters having a metallic golden shade of excellent quality and of perfect reproducibility can be manufactured as follows: during the normal preparation process for polyesters, niobium pentoxide hydrate having a water content of at least 5%, preferably of from 15 to 25%, is added in an amount yielding a niobium content of preferably from 0.001 to 0.01% by weight in the polyester end product, and their polyester is then processed in known manner by melt spinning to form filaments and fibers.

As high molecular weight synthetic linear polyesters suitable for the manufacture of these filaments and fibers having a metallic golden shade, all normal fiber-forming polyesters and copolyesters, especially polyethylene terephthalate, may be employed. During the preparation of the polyester carried out according to known methods (esterification or transesterification and polycondensation), the niobium pentoxide hydrate having the indicated water content is preferably added to the polyester precondensate. It is also possible to add the niobium pentoxide hydrate during the transesterification or one of the later reaction steps, but this is less advantageous.

The indicated water content of the niobium pentoxide hydrate is decisive for the obtention of excellent metallic golden shades in the corresponding products. This niobium pentoxide hydrate is a finely dispersed, purely white powder, and thus no color pigment. The fact that the addition of this purely white substance, and in an extremely small amount too, yields polyester filaments and fibers having such an excellent metallic golden shade, is very surprising. When, during the preparation process, niobium pentoxide hydrate is added to other polymers, for example polyamides, polyacrylonitrile and the like, the product is not dyed at all. The obtention of a golden shade is specifically linked to ester bonds in the polymer molecule. Therefore, besides pure polyester, for example also polyester amides should be used on principle for the process of the invention, but in these cases, the metallic golden shade is less pronounced than in pure polyesters.

The niobium pentoxide hydrate has no influence on the preparation process for polyesters. Also the filaments and fibers are normally manufactured by melt spinning; especially in the case of coarse-titer filaments, often even called wires, good results are obtained. The technological properties, for example strain-stress behaviour, shrinkage, reerection power, tendency to splicing and the like, are unchanged as compared with polyester filaments and fibers manufactured without adding niobium pentoxide hydrate. The fastnesses to light, abrasion and washing of the golden shade dyeings are excellent.

I ,avssaas -The condensation degree of'the polyester as well as the shade are well reproducible under the same condensation or spinning conditions without any additional work or expenditure.

Polyesters having a metallic golden shade, especially polyethylene terephthalate wires, are predominantly employed for the manufacture of rot resistant zippers for leather and plastic shaped articles, for example bags, shoes, rainwear and the like. Multi-filaments dyed in a golden shade preferably are used for those fashion woven and knitted fabrics, for which, until now, metallic filaments having only a limited corrosion resistance were employed, which latter filaments, when washed, rapidly lose their metallic luster and are only poorly compatible with the textile basic material.

The following example illustrates the invention.

EXAMPLE Dimethyl terephthalate is transesterified with ethylene glycol in the presence of zinc acetate as catalyst and at temperatures of -from 160 to 215 C. 0.0025% by weight of niobium in the form of niobium pentoxide hydrate, dispersed in ethylene glycol, is introduced into the precondensate. (The niobium pentoxide hydrate is obtained by precipitation with NH OH from niobium pentafluoride, and it is in a finely dispersed, purely white form. After a gentle drying at 120 C. in vacuo, it still contains 20% water of hydration.) Subsequently, the condensation is carried out at temperatures of from 240 to 275 C. and under a pressure of from 0.3 to 0.5 mm. Hg in the presence of Sb O as catalyst, until a specific viscosity of from 0.85 to 0.95, measured at 25 C. in a 1% solution in phenol/tetrachloroethane (3:2) is obtained. The polyester chips so modified have a goldbrown color. They are spun from an extruder with a temperature program of 275/285/275 C., drawn in a water bath at 98 C., the drawing ratio being 1:5, and

4 then shrunk on-fiat irons at 'a surface temperature of 190 C. The filaments have a metallic golden aspect and their ultimate tensile strength is from 3 to 3.5 g./dtex. at elongations at break of from 30 to 35%. Wires having a specific viscosity of more than0.9'display notendency to splicing.

What is claimedis: Q ,7

1. Filaments and fibers madefrom fiber-forming synthetic linear polyesters of a metallic golden'shade having from 0.001 to 0.01 percent by Weight of niobium.,from incorporated niobium pentoxide and calculated on total weight of polyester and niobium.

2. A process for the manufacture of filament and fibers from high molecular weight synthetic linear polyesters having a metallic golden shade, wherein, during esterification and polycondensation, or transesterification and polycondensation in the formation of polyesters, niobium pentoxide hydrate, having a water'content from 5 percent to 25 percent, is added in an amount yielding a niobium content of from/0.001 to- 0.01 percent-by weight, from niobium pentoxide, based on total weight of resulting polyester and niobium and the polyester so obtained is then melt spun to form filaments 'and fibers.

References Cited UNITED STATES PAT NTS" 3,630,990 12/1971 Neal 260 4o VP FOREIGN PATENTS 651,694 4/1951 Great Britain 260-40 LEWIS T. JACOBS, Primary Examiner US. 01. X.R. 260-40 R 

